A leading arms trade watchdog group suspects that Libya received a shipment of military equipment from Belarus, as forces loyal to Libyan leader Moammar Gadhafi began a bloody crackdown on anti-government protesters.

The Stockholm International Peace Research Institute, or SIPRI, reports that an Ilyushin IL-76 military cargo plane left Belarus two weeks ago and flew to Libya. The plane took off from Baranovichi, a Belarusian military base that inherited a huge stockpile of weapons after the collapse of the Soviet Union. The plane flew to Sebha, a base deep in the Sahara that is still controlled by Gadhafi loyalists.

The information comes from Hugh Griffiths, a British arms control expert for SIPRI. "Sebha is a very interesting airport because it is still under the control of Gadhafi. It’s surrounded by an area that is controlled by a tribe that is quite loyal, fiercely loyal, to Gadhafi. Gadhafi spent some time growing up in Sebha. He went to school there," he said.

Griffiths noted that the military cargo flight took place before a United Nations arms embargo imposed on Libya on Saturday. He said that surplus Soviet weapons from Belarus have shown up in many conflicts in Africa. "The kinds of weapons that Belarus has stockpiled, like Ukraine, are the kinds of weapons used in poor man’s wars - cheap, readily available, mass-produced weaponry, left over the from the Cold War," he said.

On Monday, U.N. Secretary-General Ban Ki-moon charged that Belarus violated an international arms embargo on the Ivory Coast by sending three attack helicopters to the forces of President Laurent Gbagbo. Last December, that West African nation’s election commission declared that Mr. Gbagbo lost presidential elections. He has refused to step down.

Belarus is also hemmed in by international sanctions imposed after disputed presidential elections late last year. After the voting on December 19, Belarus’ President Alexander Lukashenko declared victory and threw most of his opponents in jail.

"It is straightforward defamation because we are not selling arms or any type of weapons to Libya," said Belarus Foreign Ministry spokesman Andrei Savinykh speaks from Minsk.

But 18 months ago, Khamis Gadhafi, the Libyan leader’s youngest son, visited Belarus to watch military exercises with President Lukashenko and Russia’s President Dmitry Medvedev. A graduate of Russian military academies, Khamis Gadhafi is a fluent Russian speaker and has spoken publicly about buying arms from Belarus.

In the current uprising, he is leading the Khamis Brigade, a special forces unit, in attacks on rebels around Tripoli.

SIPRI expert Griffiths said that last week, a Falcon 900 executive jet belonging to Moammar Gadhafi flew twice into Minsk airport. He said the passenger seats were in place, ruling out the transport of heavy cargo.

Griffiths noted that Mr. Gadhafi maintained close ties in the 1990s with West African warlords - gang leaders who paid their bills with diamonds. "That is one of the very few items you can ship out on an executive jet that is non-traceable. This is a couple of days before the U.N. freeze came into effect," he said.

"What we are facing here, I believe, is clear and open speculation, and again defamation. Because I can assure you that no flights from Libya entered Belarus during those days," said Foreign Ministry spokesman Savinykh, from From Minsk.

With both the governments of Libya and Belarus now under the magnifying glass of international sanctions, scrutiny of this shadowy relationship is expected to only increase in coming days.